Kia Forte: Engine Electrical System / Charging System

Kia Forte 2019-2024 (BD) Service Manual / Engine Electrical System / Charging System

Components and components location

Components

① ECM

② Battery

③ Alternator

④ Starter

⑤ Instrument Cluster

⑥ Ignition switch or start/stop button

⑦ Battery sensor

⑧ Hood switch

Description and operation

Description

The charging system included a battery, an alternator with a built-in regulator, and the charging indicator light and wire.

The Alternator has eight built-in diodes, each rectifying AC current to DC current.

Therefore, DC current appears at alternator "B" terminal.

In addition, the charging voltage of this alternator is regulated by the battery voltage detection system.

The alternator is regulated by the battery voltage detection system. The main components of the alternator are the rotor, stator, rectifier, capacitor brushes, bearings and V-ribbed belt pulley. The brush holder contains a built-in electronic voltage regulator.

Alternator Management System

Alternator management system controls the charging voltage set point in order to improve fuel economy, manage alternator load under various operating conditions, keep the battery charged, and protect the battery from over-charging. ECM controls generating voltage by duty cycle (charging control, discharging control, normal control) based on the battery conditions and vehicle operating conditions.

The system conducts discharging control when accelerating a vehicle. Vehicle reduces an alternator load and consumes an electric power form a battery.

The system conducts charging control when decelerating a vehicle. Vehicle increases an alternator load and charges a battery.

Schematic diagrams

Circuit Diagram

Repair procedures

Inspection

Inspection Item

•	Battery efficiency inspection

•	Battery voltage inspection

•	Charging voltage insptection

•	General inspection

•	Terminal tightening state inspection

•	Engine/ transaxle ground state inspection

•	Wiring harness ground state inspection

•	Electrical Specified Value Inspection

•	Vehicle parasitic current inspection

•	Battery capacity inspection

Battery Efficiency Inspection

•	Check that the battery cables are connected to the correct terminals.

•	Disconnect the battery cables when the battery is given a quick charge.

•	Never disconnect the battery while the engine is running.

•	Inspect the battery test using the load tester and battery tester.

Battery Voltage Inspection

1.	After having driven the vehicle and in the case that 20 minutes have not passed after having stopped the engine, turn the ignition switch ON and turn on the electrical system (headlamp, blower motor, rear defogger etc.) for 60 seconds to remove the surface charge.

2.	Turn the ignition switch OFF and turn off the electrical systems.

Measure the battery voltage between the negative (-) and positive (+) terminals of the battery.

Standard voltage :

Approximately 12.5 - 12.9V [20°C (68°F)]

If the voltage is less than specification, charge the battery.

General Inspection

1.	Check that the battery terminals are not loose or corroded. (Refer to Charging System - "Battery")

Check the fuses for continuity.

Alternator Fuse

(1)	Check the alternator fuse for continuity.

(2)

Measure the voltage as shown in the image below.

Standard value : Approximately 0 V

(3)

If the alternator fuse is blown, replace it as in the procedure below:

a.	Turn ignition switch OFF and disconnect the battery negative (-) terminal.

b.	Remove the battery positive (+) cable mounting nuts.

c.	Replace the norminal alternator fuse or battery cable.

d.	Install in the reverse order of removal.

Inspect Drive Belt

(1)

Visually check the belt for excessive wear, frayed cords etc.

If any defect has been found, replace the drive belt.

•	Cracks on the rib side of a belt are considered acceptable. If the belt has chunks missing from the ribs, it should be replaced.

4.	Measure and adjust drive belt tension. (Refer to Engine Mechanical System - "Drive Belt")

Visually check alternator wiring and listen for abnormal noises.

(1)	Check that the wiring is in good condition.

(2)	Check that there is no abnormal noise from the alternator while the engine is running.

Check Discharge Warning Light Circuit

(1)	Warm up the engine and then turn it off.

(2)	Turn off all accessories.

(3)	Turn the ignition switch "ON". Check that the discharge warning light is lit.

(4)	Start the engine. Check that the light is lit. If the light does not go off as specified, troubleshoot the discharge light circuit.

Terminal Tightening State Inspection

•	Alternator B+ terminal state

•	Alternator B+ termina tightening nut

•	Battery positive (+) terminal state

•	Battery positive (+) terminal tightening nut state

•	Battery negative (-) terminal state

•	Battery negative (-) terminal tightening nut state

•	Battery negative (-) terminal mounting bolt tightening state (Chassis ground)

•	Battery sensor negative (-) terminal state (With battery sensor)

•	Battery sensor negative (-) terminal tightening nut state (With battery sensor)

•	Battery sensor negative (-) terminal mounting bolt tightening state (Chassis ground) [With battery sensor]

•	Engine room fuse & relay box positive (+) harness state

•	Engine room fuse & relay box positive (+) harness tightening nut state

•	Check the status of ground fault by chassis paint

Inspection Component Location

1. Alternator B+ terminal
2. Engine room fuse & relay box positive (+) terminal
3. Battery negative (+) terminal

4. Battery negative (-) terminal
5. Chassis ground

Engine/ Transaxle Ground State Inspection

•	Ground state

•	Mounting bolt tightening state (Chassis)

•	Mounting bolt tightening state (Engine)

•	Check the status of ground fault by chassis paint

Wiring harness ground state inspection

•	Ground state

•	Mounting bolt tightening state (Chassis)

•	Mounting bolt tightening state (Engine)

•	Check the status of ground fault by chassis paint

1. Engine ground (Engine ↔ Chassis)
2. Transaxle ground (Transaxle ↔ Chassis)

Check the ground point.

(Refer to ETM Harness Layout - "Ground Point")

Electrical Specified Value Inspection (Using the Voltmeter and Ammeter)

Voltage Drop Test of Alternator Output Wire

This test determines whether or not the wiring between the alternator "B" terminal and the battery (+) terminal is good by the voltage drop method.

(1)

Preparation

a.	Turn the ignition switch to "OFF".

Disconnect the output wire from the alternator "B" terminal. Connect the (+) lead wire of ammeter to the "B" terminal of alternator and the (-) lead wire of ammeter to the output wire. Connect the (+) lead wire of voltmeter to the "B" terminal of alternator and the (-) lead wire of voltmeter to the (+) terminal of battery.

(2)

Test

a.	Start the engine.

b.	Turn on the headlamps and blower motor, adjust the engine speed until the ammeter indicates 20A and read the voltmeter.

(3)

Result

The voltmeter may indicate the standard value.

Standard value : 0.2V max

If the value of the voltmeter is higher than expected (above 0.2V max.), poor wiring is suspected. In this case check the wiring from the alternator "B" terminal to the battery (+) terminal. Check for loose connections, color change due to an over-heated harness, etc. Correct them before testing again.

c.	Upon completion of the test, set the engine speed at idle.Turn off the headlamps, blower motor and the ignition switch.

Output Current Test

This test determines whether or not the alternator gives an output current that is equivalent to the normal output.

(1)

Preparation

Prior to the test, check the following items and correct as necessary.

Check the battery installed in the vehicle to ensure that it is in good condition. Refer to the "Battery" section for checking battery.

The battery used to test the output current should be partially discharged.

With a fully charged battery, the test may not be conducted correctly due to an insufficient load.

Check the tension of the alternator drive belt. Refer to the "Inspect drive belt" section for checking the belt tension.

b.	Turn off the ignition switch.

c.	Disconnect the battery ground cable.

d.	Disconnect the alternator output wire from the alternator "B" terminal.

Connect a DC ammeter (0 to 150A) in series between the "B" terminal and the disconnected output wire. Be sure to connect the (-) lead wire of the ammeter to the disconnected output wire.

Tighten each connection securely, as a heavy current will flow. Do not rely on clips.

f.	Connect a voltmeter (0 to 20V) between the "B" terminal and ground. Connect the (+) lead wire to the alternator "B" terminal and (-) lead wire to a good ground.

g.	Connect the battery ground cable.

h.	Leave the engine hood open.

(2)

Test

a.	Check to see that the voltmeter reads the same value as the battery voltage. If the voltmeter reads 0V, open circuit in the wire between alternator "B" terminal and battery (+) terminal or poor grounding is suspected.

b.	Start the engine and turn on the headlamps.

Set the headlamps to high beam and the heater blower switch to HIGH, quickly increase the engine speed to 2,500 rpm and read the maximum output current value indicated by the ammeter.

•	After the engine start up, the charging current quickly drops. Therefore, the above operation must be done quickly to read the maximum current value correctly.

(3)

Result

The ammeter reading must be higher than the limit value. If it is lower despite the alternator output wire is in good condition, remove the alternator from the vehicle and test it.

Limit value : 60% of the voltage rate

• The nominal output current value is shown on the nameplate affixed to the alternator body.

•

The output current value changes with the electrical load and the temperature of the alternator itself. Therefore, the nominal output current may not be obtained. If such is the case, keep the headlamps on to discharge the battery or use lights of other vehicles to increase the electrical load.

The nominal output current may not be obtained if the temperature of the alternator itself or ambient temperature is too high. In such a case, reduce the temperature before testing again.

b.	Upon completion of the output current test, lower the engine speed to idle and turn off the ignition switch.

c.	Disconnect the battery negative (-) terminal.

d.	Remove the ammeter and voltmeter and the engine tachometer.

e.	Connect the alternator output wire to the alternator "B" terminal.

f.	Connect the battery negative (-) terminal.

Regulated Voltage Test

The purpose of this test is to check that the electronic voltage regulator controls voltage correctly.

(1)

Preparation

Prior to the test, check the following items and correct if necessary.

Check that the battery installed on the vehicle is fully charged. Refer to the "Battery" section for checking the battery.

Check the alternator drive belt tension. Refer to the "Inspect drive belt" section for checking the belt tension.

b.	Turn ignition switch to "OFF".

c.	Disconnect the battery negative (-) terminal.

d.	Connect a digital voltmeter between the "B" terminal of the alternator and ground. Connect the (+) lead of the voltmeter to the "B" terminal of the alternator. Connect the (-) lead to good ground or the battery (-) terminal.

e.	Disconnect the alternator output wire from the alternator "B" terminal.

f.	Connect a DC ammeter (0 to 150A) in series between the "B" terminal and the disconnected output wire. Connect the (-) leadwire of the ammeter to the disconnected output wire.

g.	Connect the battery negative (-) terminal.

(2)

Test

Turn on the ignition switch and check to see that the voltmeter indicates the following value.

Voltage : Battery voltage

If it reads 0V, there is an open circuit in the wire between the alternator "B" terminal and the battery and the battery (-) terminal.

b.	Start the engine. Keep all lights and accessories off.

c.	Run the engine at a speed of about 2,500 rpm and read the voltmeter when the alternator output current drops to 10A or less

(3)

Result

If the voltmeter reading doesn't agree with the standard value, the voltage regulator or the alternator is faulty.

Regulated Voltage : 11.7-15.3V

b.	If the voltmeter reading doesn't agree with the standard value, the voltage regulator or the alternator is faulty.

c.	Disconnect the battery negative (-) terminal.

d.	Remove the voltmeter and ammeter.

e.	Connect the alternator output wire to the alternator "B" terminal.

f.	Connect the battery negative (-) terminal.

Electrical Specified Value Inspection (Using the Voltmeter and Clamp type Ammeter)

Voltage Drop Test of Alternator Output Wire

This test determines whether or not the wiring between the alternator "B" terminal and the battery (+) terminal is good by the voltage drop method.

(1)

Preparation

a.	Turn the ignition switch to "OFF".

b.	Install the clamp type ammeter between battery positive (+) and alternator "B" terminal.

c.	Connect the (+) lead wire of voltmeter to the "B" terminal of alternator and the (-) lead wire of voltmeter to the (+) terminal of battery.

(2)

Test

a.	Start the engine.

b.	Turn on the headlamps and blower motor, adjust the engine speed until the ammeter indicates 20A and read the voltmeter.

(3)

Result

The voltmeter may indicate the standard value.

Standard value : 0.2V max

c.	Upon completion of the test, set the engine speed at idle.Turn off the headlamps, blower motor and the ignition switch.

Output Current Test

This test determines whether or not the alternator gives an output current that is equivalent to the normal output.

(1)

Preparation

Prior to the test, check the following items and correct as necessary.

Check the battery installed in the vehicle to ensure that it is good condition. Refer to the "Battery" section for checking the battery.

The battery used to test the output current should be partially discharged.

With a fully charged battery, the test may not be conducted correctly due to an insufficient load.

Check the tension of the alternator drive belt. Refer to the "Inspect drive belt" section for checking the belt tension.

b.	Turn off the ignition switch.

c.	Disconnect the battery negative (-) terminal.

d.	Install the clamp type ammeter between battery positive (+) and alternator "B" terminal.

Connect a DC ammeter (0 to 150A) in series between the "B" terminal and the disconnected output wire. Be sure to connect the (-) lead wire of the ammeter to the disconnected output wire.

Tighten each connection securely, as a heavy current will flow. Do not rely on clips.

f.	Connect a voltmeter (0 to 20V) between the "B" terminal and ground. Connect the (+) lead wire to the alternator "B" terminal and (-) lead wire to a good ground.

g.	Connect the battery negative (-) terminal.

h.	Leave the engine hood open.

(2)

Test

a.	Check to see that the voltmeter reads the same value as the battery voltage. If the voltmeter reads 0V, open circuit in the wire between alternator "B" terminal and battery (+) terminal or poor grounding is suspected.

b.	Start the engine and turn on the headlamps.

Set the headlamps to high beam and the heater blower switch to HIGH, quickly increase the engine speed to 2,500 rpm and read the maximum output current value indicated by the ammeter.

•	After the engine start up, the charging current quickly drops. Therefore, the above operation must be done quickly to read the maximum current value correctly.

(3)

Result

The ammeter reading must be higher than the limit value. If it is lower despite the alternator output wire is in good condition, remove the alternator from the vehicle and test it.

Limit value : 60% of the voltage rate

• The nominal output current value is shown on the nameplate affixed to the alternator body.

•

The nominal output current may not be obtained if the temperature of the alternator itself or ambient temperature is too high. In such a case, reduce the temperature before testing again.

b.	Upon completion of the output current test, lower the engine speed to idle and turn off the ignition switch

c.	Disconnect the battery negative (-) terminal.

d.	Remove the ammeter and voltmeter and the engine tachometer.

e.	Connect the alternator output wire to the alternator "B" terminal.

f.	Connect the battery negative (-) terminal.

Regulated Voltage Test

The purpose of this test is to check that the electronic voltage regulator controls voltage correctly.

(1)

Preparation

Prior to the test, check the following items and correct if necessary.

Check that the battery installed on the vehicle is fully charged. Refer to the "Battery" section for checking the battery.

Check the alternator drive belt tension. Refer to the "Inspect drive belt" section for checking the belt tension.

b.	Turn ignition switch to "OFF".

c.	Disconnect the battery negative (-) terminal.

d.	Connect a digital voltmeter between the "B" terminal of the alternator and ground. Connect the (+) lead of the voltmeter to the "B" terminal of the alternator. Connect the (-) lead to good ground or the battery (-) terminal.

e.	Disconnect the alternator output wire from the alternator "B" terminal.

f.	Connect a DC ammeter (0 to 150A) in series between the "B" terminal and the disconnected output wire.Connect the (-) lead wire of the ammeter to the disconnected output wire.

g.	Connect the battery negative (-) terminal.

(2)

Test

Turn on the ignition switch and check to see that the voltmeter indicates the following value.

Voltage : Battery voltage

If it reads 0V, there is an open circuit in the wire between the alternator "B" terminal and the battery and the battery (-) terminal.

b.	Start the engine. Keep all lights and accessories off.

c.	Run the engine at a speed of about 2,500 rpm and read the voltmeter when the alternator output current drops to 10A or less

(3)

Result

If the voltmeter reading does not agree with the standard value, the voltage regulator or the alternator is faulty.

Regulated Voltage : 11.7-15.3V

b.	If the voltmeter reading does not agree with the standard value, the voltage regulator or the alternator is faulty.

c.	Disconnect the battery negative (-) terminal.

d.	Remove the voltmeter and ammeter.

e.	Connect the alternator output wire to the alternator "B" terminal.

f.	Connect the battery negative (-) terminal.

Vehicle parasitic current inspection

[Using the Ammeter]

1.	Turn the all electric devices OFF, and then turn the ignition switch OFF.

Close all doors except the engine hood, and then lock all doors.

(1)	Disconnect the hood switch connector.

(2)	Close the trunk lid.

(3)	Close the doors or remove the door switches.

Wait for a few minutes until the vehicle’s electrical systems go to sleep mode.

•	For an accurate measurement of a vehicle parasitic current, all electrical systems should go to sleep mode. (It takes at least one hour or at most one day.) However, an approximate vehicle parasitic current can be measured after 10-20 minutes.

Connect an ammeter in series between the battery (-) terminal and the ground cable, and then disconnect the clamp from the battery (-) terminal slowly.

•

Be careful that the lead wires of an ammeter do not come off from the battery (-) terminal and the ground cable to prevent the battery from being reset. In case the battery is reset, connect the battery cable again, and then start the engine or turn the ignition switch ON for more than 10 sec. Repeat the procedure from No. 1.

To prevent the battery from being reset during the inspection:

1)	Connect a jump cable between the battery (-) terminal and the ground cable.

2)	Disconnect the ground cable from the battery (-) terminal.

3)	Connect an ammeter between the battery (-) terminal and the ground cable.

4)	After disconnecting the jump cable, read the current value of the ammeter.

Read the current value of the ammeter.

•	If the parasitic current is over the limit value, search for abnormal circuit by removing the fuses one by one and checking for parasitic current.

•	Reconnect only the fuse suspected of parasitic current and search for the trouble unit by removing the components connected to the circuit one by one until the parasitic draw drops below limit value.

Limit value (after 10-20 min.) : Below 50mA

[Using the Clamp type Ammeter]

1.	Turn the all electric devices OFF, and then turn the ignition switch OFF.

Close all doors except the engine hood, and then lock all doors.

(1)	Disconnect the hood switch connector.

(2)	Close the trunk lid.

(3)	Close the doors or remove the door switches.

Wait for a few minutes until the vehicle’s electrical systems go to sleep mode.

•	For an accurate measurement of a vehicle parasitic current, all electrical systems should go to sleep mode. (It takes at least one hour or at most one day.) However, an approximate vehicle parasitic current can be measured after 10-20 minutes.

4.	Install the clamp type ammerter on battery negative (-) terminal.

Read the current value of the ammeter.

•	If the parasitic current is over the limit value, search for abnormal circuit by removing the fuses one by one and checking for parasitic current.

•	Reconnect only the fuse suspected of parasitic current and search for the trouble unit by removing the components connected to the circuit one by one until the parasitic draw drops below limit value.

Limit value (after 10-20 min.) : Below 50mA

Troubleshooting

•	Be careful not to short-circuit the wiring by the body or other wirings.

•	In case of discharging problem, measure dark current at all times. (Charging System - "Dark Current Inspection").

•	When checking the alternator main fuse, perform continuity test and voltage test between terminals as well as visual check to confirm normal operation.

•	When checking the ground, repair or replace after inspecting for defective ground cable, defective installation or defective contact due to foreign object.

•	It is not recommended to use non-authentic parts as installing non-authentic parts may cause malfunction of charging system.

•	Be careful as misassembly may cause short-circuit of wiring, which may result in battery discharge.

•	As it will reset and appear as normal if the battery negative (-) terminal is disconnected while measuring dark current, measure by using a hook meter without disconnecting the negative (-) terminal.

•	Note that there may be various phenomenons / possible causes / repair measures apart from above.

•	For more effective repairs, refer to DTC guide and ETM.

Symptom	Suspected Area	Remedy
Charging warning lamp does not turn on during IG ON.	Broken alternator main fuse	Inspect / Repair / Replace fuse.
	Broken instrument cluster fuse	Inspect / Repair / Replace fuse.
	Broken instrument cluster internal bulb	Inspect / Repair / Replace instrument cluster.
	Defective connection of wiring connector	Inspect / Repair / Replace wiring connection.
	Defective voltage regulator or alternator	Inspect / Repair / Replace voltage regulator or alternator.
	Defective connection of battery terminal	Inspect tightening of (+) and (-) battery terminals to specified torque.
	Communication error	Inspect wiring between regulator and ECM.
		Inspect transmission signal of ECM.
		Inspect / Repair / Replace alternator if the wiring and ECM are normal.
Charging warning lamp does not turn off during engine running.	Worn drive belt or lack of tension	Inspect / Repair / Replace drive belt.
	Defective connection, corroded or worn battery cable	Inspect connection of battery cable and Inspect / Repair / Replace cable.
	Broken alternator main fuse	Inspect / Replace alternator main fuse or battery cable.
	Defective voltage regulator or alternator	Inspect / Replace voltage regulator or alternator.
	Defective wiring	Inspect / Replace wiring.
	Defective instrument cluster	Inspect / Replace instrument cluster
	Slip in alternator pulley	Inspect / Replace alternator pulley.
	Slip in alternator pulley	Adjust tension / Replace drive belt.
	Defective connection of battery terminal	Inspect tightening of (+) and (-) battery terminals to specified torque.
Charging warning lamp turns on.	Slip, worn or lack of tension in drive belt	Adjust tension / Replace drive belt.
	Slip, worn or lack of tension in drive belt	Inspect / Replace auto tensioner (only for auto tensioner type).
	Error in Alternator Management System (AMS) voltage	Inspect battery sensor connecting harness and connection with body.
	Error in battery sensor	Inspect / Repair / Replace battery sensor.
	Short between battery sensor wiring and body	Inspect / Repair / Replace battery sensor.
	Defective alternator L terminal output power	Inspect / Repair / Replace alternator or regulator.
	Degradation due to defective contact of battery (+) terminal	Check tightening to specified torque / Inspect / Repair / Replace battery wiring.
	Short in alternator connecting extension connector internal pin	Inspect / Repair / Replace wiring.
	Short circuit between body and mission ground	Inspect / Repair / Replace ground.
	Communication error	Inspect / Repair / Replace wiring between regulator and ECM.
		Inspect transmission signal of ECM.
		Inspect / Repair / Replace alternator if wiring and ECM are normal.
	Short in the middle of connection to alternator L terminal (L terminal applied vehicle model)	Inspect / Repair / Replace wiring.
	Drive belt rotation stops due to slip in crankshaft damper pulley or defective pulley.	Inspect or replace crankshaft damper pulley / Inspect, repair or replace drive belt tensioner bearing.
	Slip, worn or lack of tension in drive belt	Adjust tension / Inspect / Repair / Replace drive belt.
	Defective voltage regulator	Inspect / Repair / Replace voltage regulator.
	Defective alternator	Inspect / Repair / Replace alternator.
	Broken alternator main fuse	Inspect / Repair / Replace alternator main fuse or battery wiring cable.
	Defective ground	Inspect / Repair / Replace ground.
	Discharged battery	Adjust tension / Inspect / Repair / Replace drive belt.
		Inspect / Repair / Replace wiring connection.
		Inspect / Repair / Replace alternator main fuse.
		Inspect / Repair / Replace alternator.
		Inspect / Repair / Replace voltage regulator.
		Inspect / Repair / Replace battery unit.
		Inspect for dark current / Repair / Replace.
		Learn / Inspect / Repair / Replace battery sensor.
		Inspect for short / Repair / Replace battery cable.
		Inspect / Repair / Replace ECM.
		Inspect / Repair / Replace body electrical related parts.
		Inspect / Repair / Replace installation status of alternator connector.
		Inspect / Repair / Replace tightening of (+) and (-) battery terminals to specified torque.
Swollen battery	Defective battery	Inspect / Replace battery.
	Defective voltage regulator or alternator	Inspect / Repair / Replace voltage regulator or alternator.
	Defective charging related parts or wiring	Inspect / Repair / Replace charging related parts and wiring.
After inspection, repair or replace related parts in case of malfunction.

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